Effectiveness factor naphthalene oxidation

In the aromatic-ring-annelated oxepin series the resonance effect is clearly the major influence dominating other factors (e.g. temperature, solvent, etc.) which affect the oxepin-arene oxide equilibrium. It is however very difficult to exclude the presence of a minor (spectroscopically undetectable) contribution from either tautomer at equilibrium. This problem has been investigated by the synthesis of chiral arene oxides from polycyclic aromatic hydrocarbons (PAHs). The presence of oxepin (26) in equilibrium with naphthalene 1,2-oxide has been excluded by the synthesis of the optically active arene oxide which showed no evidence of racemization in solution at ambient temperature via the achiral oxepin (26) <79JCS(Pl)2437>. 

As in the oxepin-arene oxide system, the resonance effect will also influence the position of equilibrium in the analogous organosulfur series. Compounds (46) and (53) thus appear to exist exclusively in the thiepin form. Since the resonance factor would favor the 1,2-episulfide of naphthalene over the thiepin tautomer (54) it is highly improbable that this thiepin will be detectable at ambient temperature. Both thiepins (46) and (55) have been isolated as thermolabile compounds (78JOC3379, 81MI51700). 

Natural sunlight induced photooxidation of naphthalene in aqueous solution has also been reported by McConkey et al. to produce six major products including 1-naphthol, coumarin, and two hydroxyquinone [9]. The authors proposed that the initially formed 2 + 2 and 2 + 4 photo cyclo addition products undergo subsequent oxidation and/or rearrangement to form the observed products [9]. Grabner et al. have studied solvent effects on the photophysics of naphthalene and report that fluorescence lifetime decreases by a factor of 2.5 in aqueous solution compared to organic solvents (e.g. ethanol, hexane, acetonitrile) [10]. Based on the observed differences in naphthalene excited triplet state properties in aqueous and organic media, the decrease... 

Efforts to solubilize and isolate the P-450 monoxygenases from the microsomal membranes have been hampered by the facile conversion to a catalytically inactive form, cytochrome P-420. In 1968, however, a successful solubilization of catalytically active P-450 from hepatic microsomes was reported.30, 31 he solubilized system, which effected w-hydroxylation of fatty acids, required three coiq>onents for catalytic activity cytochrome P-450, NADPH-cytochrome c reductase, and a heat-stable, chloroform-soluble factor, the active component of which was identified as the microsomal lipid phosphatidylcholine.32 Further studies with this solubilized and reconstituted system have Indicated that the cytochrome P-450 and P-448 fractions have different catalytic activities 33-35 and that the terminal oxidase activity resides in the b-type cytochrome (P-450 or P-448) fraction rather than the cytochrome c reductase or lipid fractions.33, 36, 37 xhe cytochrome P-450 and P-448 were found to coiq>ete for reductase when present together.38 Cytochrome bs did not appear to be an obligatory component of the reconstituted systera.39 Cytochrome P-450 and P-448 fractions from rat liver were found to contain high levels of an epoxide hydrase, which can convert intermediate oxides to vicinal diols. Further purification has afforded fractions relatively free of cross-contamination of monoxygenase and hydrase enzymes. Recently, differential solubilization of monoxygenase activity towards a Type I substrate (naphthalene) and a Type II substrate (aniline) was... 

---